1. Field of the Invention
The present invention relates to a liquid dispenser, more particularly to a liquid dispenser including a part-driving unit that has a gear set and a rack driven by the gear set to drive movement of a liquid-driving unit for discharging an amount of a liquid from a liquid container.
2. Description of the Related Art
As shown in FIG. 1, Taiwanese Patent Utility Model No. M328853 discloses a conventional liquid soap dispenser including an automatic liquid discharging mechanism 11 mounted in a housing 12. The automatic liquid discharging mechanism 11 includes a base 111, a motor 112 mounted on the base 111, a gear set 113 mounted on the base 111 and driven by the motor 112, a pressing member 114 connected pivotably to the base 111, a liquid container 117 receiving a liquid soap therein, and an elastic deformable conduit 115 connected to and in liquid communication with the liquid container 117. A pushing member 116 is driven by the gear set 113 and is in contact with the pressing member 114 such that when the motor 112 is actuated, the gear set 113 drives the pushing member 116 to rotate, which, in turn, results in pivoting of the pressing member 114 to a position to squeeze the deformable conduit 115, thereby discharging the liquid soap from an outlet of the deformable conduit 115. The pushing member 116 and the pressing member 114 subsequently return to their original positions and the deformable conduit 115 returns to its original shape after discharging. The deformable conduit 115 is likely to suffer from material fatigue after a period of use due to repeated deformation.
U.S. Pat. No. 6,536,629 discloses an aerosol device including a liquid pump that defines a passage therein and that has a plunger extending into the passage and an actuating head connected to the plunger for driving movement of the plunger between closed and opened positions. The passage has an inlet adapted to be in liquid communication with a liquid container, and an outlet opposite to the liquid inlet. The actuating head is pressable such that when the actuating head is pressed by the user, the plunger is driven to move from the closed position to the opened position for drawing a liquid from the liquid container to pass through the inlet and outlet of the passage.